1. Field of the Invention
The present invention relates to a retractable (imaging) photographing lens (retractable lens barrel), the length of which is smaller in a retracted state than that in a ready-to-photograph (operational) state.
2. Description of the Related Art
Miniaturization of lens barrels incorporated in optical devices such as cameras has been in increasing demand. Above all, further miniaturization of retractable photographing lenses, specifically the length thereof in a non-operating state, has been in strong demand. To meet such demands, the inventor of the present invention has proposed a retractable photographing lens disclosed in U.S. patent application Ser. No. 10/368342 in which an optical element of a photographing optical system is retracted to a position deviating from the photographing optical axis of the photographing optical system, and at the same time, the optical element (together with other optical elements of the photographing optical system) is retracted toward a picture plane when the photographing lens is fully retracted. The mechanism achieving such complicated operations of the optical elements is required to operate with a high degree of accuracy. In a photographing lens having such an optical element retracting mechanism, it is desirable that each of the optical elements of the photographing optical system including the retractable optical element be placed in the lens barrel in a space-saving manner. However, it is difficult to place such optical elements in a space-saving manner when actuators for actuating exposure control components such as a shutter and an adjustable diaphragm are positioned in the vicinity of the retractable optical element.